Ryan (Freddie Prinze Jr. ) and Jennifer (Claire Forlani) are opposites who definitely do not attract. At least that's what they always believed. When they met as twelve-year-olds, they disliked one another. When they met again as teenagers, they loathed each other. But when they meet in college, the uptight Ryan and the free-spirited Jennifer find that their differences bind them together and a rare friendship develops.

From the moment they first meet as kids on an airplane, Jennifer and Ryan set the tone for their life-long relationship: fighting and flirting with equal skill. Over the next few years they will meet again at various intervals, developing a real passion for despising one another. But by the time they both get to the University of California at Berkeley, their decade-long antagonism starts turning to friendship - brutally honest, no-holds-barred, true-thing friendship - the kind only one unexpected thing could possibly destroy: sex.